Sultan correctly pointed out to RK that the very fact that he is calling a third person to ask whereabouts of his "wife", speaks volumes about their fragile relationship. Advantage Sultanš
RK missed an important point when Madhu was professing her love for him. She said that she would have killed Sultan had he fired the bullet. We have witnessed very recently that madhu is incapable of killing any human being.
RK, if I were you, I would be very very weary.
I doubt if it is revenge, because I doubt she is capable of taking revenge. But something tells me that she is psyched out after hearing RK's mini-story about hero-heroin, and villain.